Emergency cutoff switch for use on internal combustion engine



y 1968 K. 5. BOYER EMERGENCY CUTOFF SWITCH FOR USE ON INTERNALCOMBUSTION ENGINE Filed May 2, 1966 SYSTIFM United States Patent3,384,062 EMERGENCY CUTOFF SWITCH FOR USE ON INTERNAL COMBUSTION ENGINEKenneth G. Boyer, 707 Country Club Road, Casper, Wyo. 82601 Filed May 2,1966, Ser. No. 547,005 1 Claim. (Cl. 123-198) ABSTRACT OF THE DISCLOSUREAn automatic temperature and oil pressure responsive safety system forcutting off the ignition system of an internal combustion engine. Thesafety system includesa relay having a pair of normally closed contactsconnected in series between the ignition switch and the ignition system.The coil of the relay is connected to the electrical system supplyingthe engine through a normally closed push button cutout switch and theparallel combination'of a temperature responsive transducer and an oilresponsive transducer. The transducers are effective to energize therelay in response to a predetermined maximum temperature and/or apredetermined minimum oil pressure.

This invention generally relates to a new and useful electrical cutoffsystem for use in any combustion engine which employs electricity forignition purposes.

More particularly the invention relates to internal combustion enginesand diesels or the like and it incorporates therein a cutoff systemwhich will terminate engine ope-ration when the existence of abnormalconditions are sensed. The invention provides a cutoff circuit which iselectrically actuable or energizable so as to interrupt engine operationwhen the existence of any one or more conditions prevail in theassociated combustion engine equipment. In the disclosed construction ofthe device the cutoff circuit is associated with an internal combustiondiesel engine, this, however, is intended to be merely exemplary and notlimiting. The circuit includes two transducers which are respectivelyresponsive to temperature and oil pressure, and which operates inconjunction with a solenoid to terminate the operation of the combustionengine when certain predetermined critical oil pressure and operatingtemperatures are exceeded.

A switch is included in the device to enable the operator of theinternal combustion engine to bypass the automatic cutoff circuit whenthe engine is ignited either at low temperatures or under other abnormalconditions. This bypassing device is specifically useful when theinvention is incorporated in a diesel engine which normally is crankedto commence initial operation. The bypassing device will assure that thesolenoid switch located on the fuel pump of diesel engines has theproper operating current before the cranking operation begins, otherwisethe diesel engine will fail to initially ignite.

Presently existing systems have dashboard lights to indicate an abnormalcondition in an internal combustion engine, however, no means arepresently available to autoatically terminate the operation thereofbefore this condition creates an irreparable situation. The subjectinvention can conveniently be incorporated in existing indicatingsystems, since generally these systems have pressure and temperaturetransducers as standard items.

It is a primary object of this invention to provide a cutoff system forinternal combustion engines so that when specific abnormal conditionsare sensed, the engine will automatically terminate its operation.

It is another object of-this invention to provide a cutoff system whichis readily incorporated in presently existing internal combustionengines, so as to make the safe operation thereof automatic.

These and other objects of the present invention will become obvious byreference to the following description and accompanying drawings.

FIGURE 1 is an enlarged sectional view of the solenoid cutoff means.

FIGURE 2 is an enlarged sectional view of the bypass means.

FIGURE 3 is a diagrammatic view of the complete system, as it isincorporated in an ignition system.

With continuing reference to the accompanying drawings wherein likereference numerals designate similar parts throughout the various views,reference numeral 10 designates an ignition system as is generally usedin internal combustion engines. An oil pressure transducer 12 isprovided for grounding the ignition system when a minimum oil pressureis reached. In order to assure proper operation of an internalcombustion engine, it is necessary that a minimum oil pressure bemaintained within the engine. If this pressure falls below a certainminimum and is allowed to continue, detrimental effects will arise thatwill be harmful to future engine operation. The oil pressure transducer12 is set to ground the ignition circuit when the oil pressure reaches aminimum of 8 to 10 pounds per square inch. The device comprising thepresent invention is also adapted to ground the ignition circuit when ahigh temperature is sensed by the temperature transducer 14. This willprotect the internal combustion en ine from operating at extremely hightemperatures that may be detrimental to its operation. The temperaturetransducer 14, may be set to shut down the engine when the temperaturereaches 200 to 210 degrees. It is noted that either condition wiilterminate the engine operation when the predetermined limits arereached.

Referring specifically to FIGURES l to 3, a relay 15 is provided; it iscomposed of a solenoid 16 adapted to actuate a contact member ofelectrically conductive material which has a contact plate 20 mounted onone end thereof. The contact plate 20 is adapted to engage a contactplate 22 mounted on another contact member of electrically conductivematerial as indicated at 24. The contact plates 20 and 22 are normallyclosed, and are kept in this position by a spring-like contact member26. The spring contact is mounted on another member of electricallyconductive material as indicated at 28. Member 28 is connected throughterminal 30 to a conductor 32, which is attached to one terminal 34 ofan ignition switch 36, controlled through the ignition key 38. The otherterminal of the ignition switch 36, is connected to a battery 42.

One terminal of the core of solenoid 16 is connected to terminal 30. Theother terminal of the core 16 is connected through conductor 44 anddielectric hole 46, to terminal 48. This terminal 48 is connected tobypass switch 50 by conductor 49, the operation of which is explainedinfra. The member 24 of electrically conductive material is connected toterminal 52, which in turn is connected to ignition system 10, viaconductor 54.

FIGURE 2 specifically displays a diagrammatic side view of bypass switch50. It is shown merely as exemplary and is not intended to be limiting.The switch 50 is used to bypass the automatic cutoff system, when theengine is ignited under some abnormal condition as previously described.It is composed of a forward biased spring member 56 which maintains theautomatic cutoff system in operation, unless it is specifically desiredto be eliminated. This can be accomplished by manually dcpressing button58, which moves a cylindrical sliding body 60, connected to button 58through the rod 62. The contacts 64 and 65 are mounted on a piece ofdielectric material 68, and are maintained in electrical contact througha plate of conducting material 70. The electrical contact is furthersecured and enhanced by a spring means 72 which is located oncylindrical sliding body 60. The bypass switch 50 can be secured to thedash board 74 of an automobile or any other convenient location to theoperation of the system. A thread mount '76 is provided for thisapplication.

In operation, when the ignition system is first started under anabnormal condition, such as low temperature, the button 58 of bypassswitch 50 is depressed to insure that the engine will ignite. After theengine has ignited and is running properly the bypass switch 50 isallowed to assume its normal position, as shown in FIGURE 2. Assumingfor purposes of this operational disclosure, a low oil pressure (e.g.,below 8 to 10 p.s.i.) is sensed by oil pressure transducer 12. Thiscompletes the cutoif circuit through the following components: from oilpressure transducer 12, via wire 78 to contact 54, through con tactplate 70 to contact 66, via wire 49 to contact 48, through wire 44 tothe solenoid core 16. This energizes the solenoid core 16, which opensthe normally closed contacts 20 and 22, thereby interrupting the currentflow to the ignition system 10. This automatically terminates theoperation of the internal combustion engine. This automatic cutoffsystem, by so shutting down the operation, alleviates any damage whichmay be incurred from operating the internal combustion engine with aninternal detrimental condition.

It can be readily ascertained that the system Will perate in exactly thesame manner for a high temperature condition which may be sensed by thetemperature transducer 14. The transducers are connected in series viawire 80, so that either condition will automatically cut oif theoperation of the engine.

From the foregoing, the construction and advantages of this emergencycutoff system are readily apparent and further description is believedto be unnecessary. However, since numerous modifications will readilyoccur to those skilled in the art, after a consideration of theforegoing specification and accompanying drawings, it is not intended tolimit the invention to the precise embodiment shown and described, butall suitable modifications and equivalences may be readily resorted toif desired.

What is claimed as new is as follows.

1. In an internal combustion engine having an ignition switch and anignition system, a temperature and oil pressure responsive safety systemfor automatically cutting off said engine in response to an abnormaltemperature or oil pressure comprising:

a relay having a pair of normally closed contacts and an energizablecoil for opening said contacts,

means for connecting said pair of normally closed contacts in seriesbetween said ignition switch and said ignition system,

a spring-loaded, normally closed, push-button cutout switch fordisabling said safety system,

an oil pressure transducer having a first terminal, said oil pressuretransducer being elfective to ground said first terminal in response toa predetermined minimum pressure within said engine,

temperature transducer having a second terminal, said temperaturetransducer being responsive to a predetermined maximum enginetemperature to ground said second terminal, and

means for connecting said first and second terminals,

said spring-loaded normally closed push-button switch and saidenergizable coil in series to the junction of said ignition switch andsaid pair of normally closed contacts.

References Cited UNITED STATES PATENTS 1,770,264 7/1930 Eslinger123146.5 1,920,694 8/1933 Hancock 123-1465 2,162,174 6/1939 Jones123146.5 2,317,062 4/1943 Jervis 123146.5 X 2,358,729 9/1944 Murphy123-146.5

FOREIGN PATENTS 279,551 10/ 1927 Great Britain.

WENDELL E. BURNS, Primary Examiner.

